The invention relates to a method for measuring the size, charge, velocity, and/or concentration of particles in polydispersed systems and particle concentrations in monodispersed aerosols, and discloses a novel measuring device for performing the process.
It is known to use optical measuring processes to detect particle sizes, particle concentrations and flow velocities, and to optoelectronically convert and display the measured signals. The measuring devices necessary for this purpose are relatively expensive. Also, in these systems, the measuring result is influenced by the optical properties of the particles. In the case of particle sizes smaller than or equal to 0.1 micron, because of the Raleigh scattering effect, an optical measurement becomes more difficult or impossible.
It is further known to use electric field probes for contactless measurement of charge clouds. In view of the fact that aerosol particles are electrically charged, particle size measurements have been made with the use of electric charges, either by integrating the charge of a collecting receptacle or impact disk over time, or by measuring the charging current of the collecting receptacle or impact disk. These processes are limited in their measuring accuracy, and do not make possible any measurement of very low particle concentrations and of flow velocities.